We are in the process of setting SCADA language to control two 30 HP brush rotors in our oxidation ditch. We have never had constant DO monitoring until we installed them for this project. What an eye opener. Has anyone set up VFD's to control speed of brush rotors? My max and min rotor RPM limits are 33 - 66.

What is the eyeopener you refer to? This mainly domestic wwtp has 2 fixed speed rotors, w/out reliable DO monitoring, so I'm curious what we'd see if there was. I set one rotor to be off from 11pm to 6am, when loading is low, but it's a guess. Can't you set scada with a specific DO target and let the rotors speed vary to achieve that?